Elevator control system



Aug. 18, 1931. v V 1,819,454

ELEV ATOR CONTROL SYSTEM V Filed Nov. 19, 1927 III!!! INVENTOR Mi |Ton Baruch Patentecl Aug. I8, 1931 UNITED STATES PATENT OFFICE HILTON BAR'U'CH, OF BEVERLY HILLS, CALIFORNIA, ASSIGNOR T WESTINGHOUSE ELEC'IRIC & MANUFAC'IURIN'G COMPANY, A CORIBORA'IION OF PENNSYLV:ANIA

ELEVA'IOR CONTROL SYSTEM Applicacion filed November 19, 1927. Serial N0. 234,409.

My invention relates to control systems for motor-driven inachines and has specia] reference to contro l systems for elevators, hoists and similar machinery.

An object 0f my invention is 130 provide a control system of' the type dsigned f0r intermittent servic wherein the electrical driving device will be .at rest when no service is desired.

Another object of m'y invention is to provide a control system of the VVard-Leonard type where the driving motor-generator sei: Will be automatically Stopped when the working motor is not in substantially coutinuous service.

Another object of my invention is toprovide a control s *stem of the Ward-Leonard type wherein t e driving motor-generator set Will be shut down whenever a predetermined i;ime elapses between successive operations of the drivenmachine.

Another object of my invention is t0 provide an elevator-control system havinga Ward-Leonard drive and' having means for stopping-t-he motor-generator set whenever a predeterminedtime elapses by the successive calls for the services of the elevator.

My invention Will be described With referencga to the accompanying drawihg Wherein the so1e figure is a diagrammatic view 0f my control system as applied 130 a pushbutton-controlled elevator to be operated between the limits 0f four fioors.

Referring to the drawing, I have illustrated an elevator car C suspended upon a cable Ca which passes over a hoisting drum D to a suitable cqunterweight Cw. The hoisting drum D is directly coupled to the armature EM of a workinglevator m0- tor EM. A motor-generator set, comprising a generator G, preferably of the compound-Wound type, having its armature G and its series field windings GSF continuously c0nnected to the terminals of the elevator motor armature EM, and squirrel-" cage alternating-current motor M having its roter M directly coupled to the 'generator armature G by means of a shaft S.

The driving motor M is illustrated as being of the three-phase type having its stator windings MS connected to the threephase conductors of a suitable source of alternating-current supply designated, as I,

II, und III.

A direct-current Exciter E having its armature E Coupled to the shaft S and having its field winding EF connected in shunt relation to the armature E, is dedescribed.

The field winding EMF of the elevatof motor EM is illustrated as being permanently connected across the terminal conductors L1 and L2 WhiCh lead from the exciter E. Thus, the direction of movemeht 0f the motor EM is contiolled by the selective excitation of a separately excited field Winding GB, provided f'or the generator G, t0 be selectively Connected to the exciter comductors L1 and L2 having current traversing the winding in opposite directions through the operation of up and down-direction switches 1 and 2.

A series of push-buttons F1, F2, F3 und F4 are illustrated as being mounted at suitable locations 0n the first, second, third und. fourth fl@ors respectively, to be operated by g:rsons desiring 130 use the elevator. 'Ihe nction 0f the push buttons is to operate the controlling switches for calling the car' to the respective fioors corresponding to such buttons.

Similar push-buttons C1, C2, C3 and C are mounted upon the elevator car C to be to be operated in accordance with the movements of the elevator car C as it travels up .and down in its hatchway. The switches may be of any suitable two -position ty having the characteristic of remaining 111 either position until moved, through some outside agency, to the opposite position.

I have illustrated suitable doors D1, D2, D3 and D4 as representing the usual closures fo1; the openings in the hatchway for the first, second, third and fourth floors, respgctively. The doors ma.y be provided W1 th suitable locking devices (not shown) and may have mounted thereon the usua1 door switches, designated as 10, 11, 12 and 13, to be normally in a, closed-circuit position but operable t0 an open-circuit position through the agency of. a retiring cam RC carried by the elevator cm C, When the car is adjacent to the door.

The driving motor M 0f the motor-generator set is suitably controlled, through the operation of relays MG, AM and T, f0r comnecting the three-phase windings of the m0- t0r stator MS to the hase conductors 0f the AG supply upon suitable operation of these relays.

The relay T is provided with a dash-pot so disposed as t0 permit a rapid movement of the armature 15 of this relay When drawn upwardly but t0 retar l the downward movement of the armature for a. predetermined adjustztble length of time.

The operation of my system will best be understood When described with reference 130 an assumed elevator operation.

Assuming that the elevator is standing at the fourth 01 upperrnost floor and that all of the relays are in their illustrated positions and assuming that a erson a.t the third floor, desiring to use the 'elevator car C operates the button F3. The operation of the button .F3 completes a circuit for energizing the down-direction-determining relay DR and the cam-retiring magnet 27, which extends from the line Conductor II of the AG supply, through conductors 16 and 17, contact mernbers w of a relay AL, conductors 18 and 19, the contact members of the push button F3, conductors 20 and 21, the coil of floor relay FR3, conductor 21, the floor-selector switch 3SD (now in closed position, since the car is above the third floor), conductors 22 and 23, the coil of down-direction-determining' relay DR, conductor 24, contact members a of up-direc- .tion-determining relay UR, conductors 25 and 26, the coil 27 for the retiring cam RC and conductors 28 and 29, to line conductor I of the AC supply. The energization of the coil 27 for the retiring cam RC moves the cam out of engagement with the door switch 13, permitting this switch to close, while the energization of the down-direction-deter mining relay DR completes a circuit for operating the down-direction switch 2 which Will be hereinafter more fully described;

Up0n the closing of the door switch 13, a cir cu1fi is completed for energizing aloor relay AL which extends from line conduc tor II, through conduc'tors 16 and 17, the coil of the dem relay AL, conductor 30, door switches 13, 12, 11 and 10, in series relation, conductors 31 and 32, gute contact members 34 (such as are usually disposed t0 be closed by the Cm gute structure 35, 11 portion of which only is illustrated) and conductor 29, t0 1ine conductor 1.

The operation of the rclay AL causes the motor-generator set to be started to condition the generator G to supply the necessary operating cur1ent t0 the elevator 1notor EM. This efl:'ect is accomplished through the energization of the timed relay T, energized through contact members 0 of relay AL, the circuit for which extends from line couductor II, through conductor 16, contact members 0 of relay AL, conductor 33, the coil of timed relay T and conductor 34, t0 line conductor I. The energizution 0f reluy T raises the armature 15, permitting switch 35 130 assun1e its closed-circuit position.

Switch 35 completes a circuit for 1ela MG which extends from line conductor I through conductor 36, coil of relay MG, conduct0r 37, switch 35 and conductor 38, to' line conductor II. Relay MG completes the circuit for the motor-controlling relay AM, as hereinafter described.

It will be noted that one of the hase windingsf 40 0f the motor stator MS is permanently connected t0 line conductor I through resistor 41 and conductor 42. Thus, the closing 0f contact members a and b of relay AM connects the remaining phase windings 43 and 44 t0 the remaining phase conductors II and III by way 0f circnits which cxtend from 1ine conductor II, through conductor 45, contact members a of relay AM, conductor 46, resistors 47, comductor 48, winding 43, to the star point 49; and from line conductor III, through couductor 50, contact members b of relay AM, conductor 51, resistor 52, conductor 53, and winding 44, to star point 49. The motor M is thus started t0 drive the genemtor annuture G and the exciter armature E.

A relay is provided for each phase of the stator winding MS t0 shunt the rsistors 41, 47 and 52 from the motor stator circuits, these relays being designated, respectively, as R1, R2 and R3. The coils for the relays R1, R2 and R3 are connected in series relation with each ot,her nd are supplied with C111- rent from the exciter E.

By suitable selection of the coils for the relays R1, R2 and R3, these rela s may be caused to operate at any pre etermined speed of the motor M, since the operating current for these coils depends upon the building up of voltage in the exciter E. When thevoltage of the exciter E waches a predetermined value, the relays R1, R2 and R3 will be operated to c lose their contact member and thepeby connect the windings ot the stator MS directly t0 the supply couductors I, II and III.

As the exc'iter bilildS up voltage, directio'nswitch 2 Will be energized through the coutact members b of down-direction-determining relay DR by way of a Circuit which extends from excit'er line conductor L1, through conductors 55 and 56, contact nr1embar b of relay DR, conductor 57, the coil of down-direction switch 2, conduetor 58, contact members (Z, of relay AL (now in closedcircuit position) and conductor 59, to the exciter line conductor L2. 'lhe operation of down-direction switch 2 will cause excitation 0f the generator-sepagately-excited field winding GF in the usual manner through a circuit which extends from line conductor L1, through conductor 60, oontact members b of down-direc'tion switch 2, conductors 61 and 62, field-winding GF, conductors 63 und 64, contact members a 0f down-direction switch 2 and conductor 65, to lin6 conductor L2.

Since the field winding EMF for the ele-- vator winding EM is pennanently. connected across the exciter line conductors L1 and L2, through conductors 61 und 62, the excitation 0'f the generatorfieldwinding GF und. the

consequent supplying 0f voltage to the zumature EM 0f the elevator motor, the moto-r EM will be caused to statt to thereby move the (rar downwardly.

It Will be noted that the circuit f0i energizing the floor relay F3 traced through normally closed contact members a 0f relay' ALL and the pushbutton F3 was transferred through the operation of rka1ay AL from coutact members a t0 contact members b of this relay and, by reason 0f a self-h0lding circuit for the relay FR3, this relay was maintained in operative position q ntil the switch 3SD was opened. This holding circuit extends f10m line conductor II through conductors 16 and 17, contact members b of relay AL, conductors 64 und 65, contact members of relay FR3, Conductor 21 and then'ce through the coil of relay FR?) as previously described As the car arrives adjacent 130 the third floor, a finger SD, carried by the car, will engage the selector switch 3SD and move the same to open-circuit position, deenergizing the down-directiondetermining relay DR,

.the down-direction switch 2 and floor'relay v FR3.

out andthereby o pen the circuit to t he timed r elay T. The tim6d relay T, hoWever, does not immediately open the switch 35 to stop y the driving motor-generator s et by res'1son of the action of the dash-pot 6 which permits when running idle, causes a consumption of' current equal to that du'e to the 10Sses caused by starting the set one time. However, this time may be extended to fit the conditions of any particular installation and may depend u on other factors such as the eisti-' .mated requency of' calls for.service, thus varying the time througha wide range, from two to forty seconds, or more.

Assuming that the time allowed by the dash-pot 6 for the opening of switch 35 is 20 seconds, during which time the person who desired 130 use the car at the third floor opens the door D3 and enters the car C. Assuming that this person desires to travel to the first floor and, therefore, operates the button C1 within the car C, a circuit will be completed for energizing floor relay F Rl- Which circuit extends from line conductor II, thr ough conductors 16, 17, 18 and 67, contact members of the push-button C1, comductor 68, the coil of fl00r relay FR1, switqh 1SD (now in closed position) and conductr 23 and thence thpough the 0011 of relay DR und the c0il 27 of the retiring cam RC as pteviously described for these coi1s. The subsequen starting of the elevator, through the operation 0f the relay AL and direction switch 2, Will be performed in the same Inanner as that previously described.

The operation of the elevator in ehe upand no call buttons F1, F2, etc., are operated until the lapse of' the time allowed by the dash-pot 6 0f the timed relay T, this relay being deenergized by the opening 015 'the door switcheS 10, 11, 12 or 13 occasioned by the release 0f the retiring cam RC when the car stops at the respective floors, will open the sWitch 35 to deenergize relay MG and AM to sfiop the motor M. However, assume, thereafter', that one of the buttor'1s F1, F2, etc, or O1, C2, etc., is operated, the

. motor M Will be insfianfly started to condition the elevator to answer such call for service.

' Thus far, the starting of the motor-generator set has been described as caused by the operation of a fldor-lancling push-button F1, or push-button F2, etc. Under these conditions there is a slight delay in.the starting of the generator G on account of the time required for the motor M to accelerate to its normal speed. \Vhen a call for service is made from one of the landing buttons, such slight delay does not necessarily inconvenience the prospective passenger, since he is not macle aware of unusual clelay. However, if the car C is standing at a floor atwhich a person deSires to board'the car and the motor M is at fest, such person upon entering the car and operating the button C1, C2, etc., for the floor to Which he desires to travel, Will expcricnce the delay netzessary for the motor M to co1ne up to speed. Such delays impress themselves upon ehe mind of the person using the ehvator since l1e is ready to travel but the elevator is not and, in Order to avoid this unpleasant psychological conclition, I have proviclecl a relay BA, the coil of which is in circuit with the contact members 34:, to be energized ab all times when the car gute is closed.

When the prospective passenger opens the gute preparatory to entering the car C, relay BA Will be deenergizecl and will close its contact members, thus energizing relay T toca1ise starting of the motor M.

Hence, the motor M Will havo such time as elapses between the opening of the gate and the subsequent operation of the car button C1, etc., to accelerate it to its normal working speed. The circuit for the timed relay T, closed by deenergization of relay BA, extends from line conductor II, through conductors '69, 70, 71 and 33, the coil of v relay T and conductor 34, to line conductor I.

It will'thus be seen that I have provided a control system for an elevator using the Ward-Leonarcl drive wherein the generator driving motor Will be stopped during substantially all such times as no calls for service exist and wherein the first registered call for serv ice, after such stopping of the motor-generator Set, starts ehe set to permit the normal Operation cf the elevator thereafter. When the elevator is used only infrequently, this method of controlling the motor-generator -set results in the saving of such current as woulcl be required to drive the motor-generator set when idle. The advantage of this is particularly apparent whcn it is noted that the idling losses of a large alternating current motor, such as is required to drive the generator in an installation of the type illustrated, if ex- 5 tended over a long period of time, may

consun1e a quar1tity cf currenfi which er'- forms no valuable work and it is 0bject1onable to have this setoperating over long periods of time during which the elevator hoisting 1notor is idle.

The form of the invention described above is merely illustrative and I do not desire to be limited to any cf the details shown except insofar as they may be defined in the appended claims.

I claim as n1y invention:

l. In an elevator-controlling systern, an elevator operable past a plurality cf floors, 1notive means therefor, a motor-generator sei; for supplying energy to said motive means, call means for act-uating said m0- tive, means to cause said elevator to travel 130 any of said floors and to stop thereat, a closure for sail elevator permitting entry to said elevator, and means, operable in response to actuation of any of said call means o1 to tl1e opening of said closure for starting said motor-generator set and operably responsive to the lapse of a predetermined tlme after the stopping of said. elevator for stopping said motor-generator set.

2. In a controlling-system for an elevator operable past a pl1irality of floors, motive nieansfor said elevator, a motor-generator set for supplying energy to said motive n1eans, a closure f01 said elevator, and means operable by opening said closure for starting said motor-generator sei; and operable by the stopping of said elevator for stopping said motor-generator set upon the lapse of a precletermined time thereafter.

In testimony whereof, I have hereunto subscribed my na1ne this tenth day of N0- vetnber, 1927.

MILTON BARUCI'I. 

